<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Document</title>
	<style type="text/css">
		div{
			width: 100%;
			height: 300px;
		}
		.son1{
			width: 20%;
			background-color: red;
			height: 100%;
			/*float: left;*/
			/*float: left;*/
			display: inline-block;
			
		}
		.son2{
			width: 80%;
			background-color: green;
			height: 100%;
			/*float: left;*/
			/*float: right;*/
			display: inline-block;
			
		}
		/*p,span{
			margin: 0;
		}*/
	</style>
</head>
<body>
<div>
	<span class="son1"></span><span class="son2"></span>
</div>
	
</body>
</html>